#!/bin/sh
# Copyright (c) 2018, The Linux Foundation. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
#       copyright notice, this list of conditions and the following
#       disclaimer in the documentation and/or other materials provided
#       with the distribution.
#     * Neither the name of The Linux Foundation nor the names of its
#       contributors may be used to endorse or promote products derived
#       from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
# ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
# IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# find_recovery_partitions: systemd/init.d script to 
# dynamically find partitions used in recovery mode
#

emmc_dir=/dev/block/bootdevice/by-name
mtd_file=/proc/mtd
fstab_file=/tmp/recovery_volume_detected

ubi_device_number=9 # use a high enough number to avoid conflicts

UpdateRecoveryVolume () {
    partition=$1
    dir=$2
    fs_type=$3
    device=$4
    echo "$device       $dir     $fs_type     defaults    0   0" >> $fstab_file
}

FindAndAttachUBI() {
    partition=$1
    num_volumes=$2

    mtd_block_number=`cat $mtd_file | grep -i $partition | sed 's/^mtd//' | awk -F ':' '{print $1}'`
    if [ -z "$mtd_block_number" ]; then
        echo "MTD : Partition $partition not found" > /dev/kmsg
    else
        echo "MTD : Attaching UBI device: /dev/mtdblock$mtd_block_number for $partition @$ubi_device_number" > /dev/kmsg

        ubiattach -m $mtd_block_number -d $ubi_device_number /dev/ubi_ctrl
        count=1000 # wait for the ubi-device node to be created for a max of (1000 * 0.010 = ) 10 seconds
        while [ 1 ]; do
            if [ -c /dev/ubi${ubi_device_number} ]; then
                echo "/dev/ubi${ubi_device_number} created" > /dev/kmsg
                break
            else
                count=$(($count - 1))
                if [ $count -lt 1 ]; then
                    echo "/dev/ubi${ubi_device_number} not yet created, rebooting" > /dev/kmsg
                    /sbin/reboot
                    break
                else
                    sleep 0.010
                fi
            fi
        done

        i=0
        while [ "$i" -lt "$num_volumes" ]; do
            count=500 # wait for the ubi volume node to be created, for max 5 seconds
            volume_node="/dev/ubi${ubi_device_number}_${i}"
            while [ 1 ]; do
                if [ -c $volume_node ]; then
                    echo "$volume_node created, proceeding" > /dev/kmsg
                    break
                else
                    count=$(($count - 1))
                    if [ $count -lt 1 ]; then
                        echo "$volume_node not yet created, rebooting .." > /dev/kmsg
                        /sbin/reboot
                        break
                    else
                        echo "$volume_node not yet created, checking again .." > /dev/kmsg
                        sleep 0.010
                    fi
                fi
            done
            i=$(($i + 1))
        done
        ubi_device_number=$(($ubi_device_number + 1))
    fi

    # for debugging purposes, log the list of
    # ubi devices and gluebi devices to kmsg
    ls -al /dev | grep -i "ubi" > /dev/kmsg
    cat /proc/mtd > /dev/kmsg
}

FindAndMountUBI () {
    volume=$1
    dir=$2
    fstab_only="$3"

    echo "MTD : Looking for UBI volume : $dir for $volume" > /dev/kmsg
    mkdir -p $dir

    # Skip ubi0 for recoveryfs
    for ubidev in /dev/ubi[1-99]_*; do
        volname=`ubinfo $ubidev | grep Name\: | awk '{print $2}'`
        if [ "$volname" == "$volume" ]; then
            echo "Found Volume: $volname" > /dev/kmsg
            if [ "$fstab_only" != "1" ]; then
                mount -t ubifs $ubidev $dir -o bulk_read
                echo "MTD : Mounting of $ubidev on $dir done" > /dev/kmsg
            fi
            UpdateRecoveryVolume $volume $dir "ubifs" $ubidev
            break
        fi
    done
}

FindAndMountSquashfsToGluebi () {
    volume=$2
    dir=$3
    fstab_only="$4"

    gluebi_mtd_block_number=`cat $mtd_file | grep -i $volume | sed 's/^mtd//' | awk -F ':' '{print $1}'`

    if [ "$fstab_only" != "1" ]; then
        mount -t squashfs /dev/mtdblock${gluebi_mtd_block_number} $dir
    fi

    UpdateRecoveryVolume $volume $dir "squashfs" /dev/block/bootdevice/by-name/$1

    # create symlink from /dev/block/bootdevice/by-name/<partition>
    # to the gluebi-mtd device
    mkdir -p /dev/block/bootdevice/by-name
    ln -sf /dev/mtdblock${gluebi_mtd_block_number} /dev/block/bootdevice/by-name/$1
}

FindAndMountEXT4 () {
    partition=$1
    dir=$2
    fstab_only="$3"

    mmc_block_device=/dev/block/bootdevice/by-name/$partition

    echo "EMMC : Looking for EXT4 block device : $dir for $partition"
    mkdir -p $dir
    if [ "$fstab_only" != "1" ]; then
        mount -t ext4 $mmc_block_device $dir -o relatime,data=ordered,noauto_da_alloc,discard
        echo "EMMC : Mounting of $mmc_block_device on $dir done"
    fi
    UpdateRecoveryVolume $1 $2 "ext4" $mmc_block_device
}

FindAndMountMTD () {
    partition=$1
    dir=$2

    mtd_block_device=`cat /proc/mtd | grep -i $partition | sed 's/^mtd/mtdblock/' | awk -F ':' '{print $1}'`
    echo "Detected block device /dev/${mtd_block_device} for $partition" > /dev/kmsg
    mkdir -p $dir
    mount -t mtd /dev/$mtd_block_device $dir
    echo "Mounting of /dev/$mmc_block_device on $dir done" > /dev/kmsg

    UpdateRecoveryVolume $1 $2 "mtd" /dev/$mtd_block_device
}

echo -n > $fstab_file

if [ -d $emmc_dir ]
then
    fstype="EXT4"
    eval FindAndMountEXT4 system   /system   1
    eval FindAndMountEXT4 userdata /data     1
    eval FindAndMountEXT4 cache    /cache
elif grep "rootfstype=squashfs" /proc/cmdline
then
    # the recoveryfs image has squashfs on it, so
    # we assume that system's fs is squashfs as well
    eval FindAndAttachUBI system 5
    eval FindAndMountSquashfsToGluebi system rootfs  /system  1
    eval FindAndMountUBI usrfs   /data    1
    eval FindAndMountUBI cachefs /cache
else
    fstype="UBI"
    eval FindAndAttachUBI system 5
    eval FindAndMountUBI rootfs  /system  1
    eval FindAndMountUBI usrfs   /data    1
    eval FindAndMountUBI cachefs /cache
fi

FindAndMountMTD misc /misc

exit